I like the stacking of the analog/digital pin idea, it makes it clearer that the analog pins can do double duty as higher number digital pins.

I don't really like the notes field interrupting the grid though. Having a continuous grid you can scan your eyes up and down really makes a chart like this much more readable. I think simply minimizing the notes as much as possible, and putting them in with the description is a better way to go. Some of the comments seem unrelated to pin requirements (Arduino ethernet/xbee)

We could lobby for a wider playground page, that would alleviate this whole problem.